﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Media;

namespace Joyeon.Utils
{
    public class VisualTreeHelperUtil
    {
        /// <summary>
        /// Finds a Child of a given item in the visual tree. 
        /// </summary>
        /// <param name="parent">A direct parent of the queried item.</param>
        /// <typeparam name="T">The type of the queried item.</typeparam>
        /// <param name="childName">x:Name or Name of child. </param>
        /// <returns>The first parent item that matches the submitted type parameter. 
        /// If not matching item can be found, 
        /// a null parent is being returned.</returns>
        public static T FindChild<T>(DependencyObject parent, string childName)
           where T : DependencyObject
        {
            // Confirm parent and childName are valid. 
            if (parent == null) return null;

            T foundChild = null;

            int childrenCount = VisualTreeHelper.GetChildrenCount(parent);
            for (int i = 0; i < childrenCount; i++)
            {
                var child = VisualTreeHelper.GetChild(parent, i);
                // If the child is not of the request child type child
                T childType = child as T;
                if (childType == null)
                {
                    // recursively drill down the tree
                    foundChild = FindChild<T>(child, childName);

                    // If the child is found, break so we do not overwrite the found child. 
                    if (foundChild != null) break;
                }
                else if (!string.IsNullOrEmpty(childName))
                {
                    var frameworkElement = child as FrameworkElement;
                    // If the child's name is set for search
                    if (frameworkElement != null && frameworkElement.Name == childName)
                    {
                        // if the child's name is of the request name
                        foundChild = (T)child;
                        break;
                    }
                }
                else
                {
                    // child element found.
                    foundChild = (T)child;
                    break;
                }
            }

            return foundChild;
        }

        public DependencyObject FindChild(DependencyObject o, Type childType)
        {
            DependencyObject foundChild = null;
            if (o != null)
            {
                int childrenCount = VisualTreeHelper.GetChildrenCount(o);
                for (int i = 0; i < childrenCount; i++)
                {
                    var child = VisualTreeHelper.GetChild(o, i);
                    if (child.GetType() != childType)
                    {
                        foundChild = FindChild(child, childType);
                    }
                    else
                    {
                        foundChild = child;
                        break;
                    }
                }
            }
            return foundChild;
        }

        public static T FindVisualParent<T>(UIElement element) where T : UIElement
        {
            UIElement parent = element; while (parent != null)
            {
                T correctlyTyped = parent as T; if (correctlyTyped != null)
                {
                    return correctlyTyped;
                }
                parent = VisualTreeHelper.GetParent(parent) as UIElement;
            } return null;
        }

        public static T FindChild<T>(DependencyObject parent) where T : DependencyObject
        {
            if (parent == null) return null;

            T childElement = null; int childrenCount = VisualTreeHelper.GetChildrenCount(parent); for (int i = 0; i < childrenCount; i++)
            {
                var child = VisualTreeHelper.GetChild(parent, i);
                T childType = child as T; if (childType == null)
                {
                    childElement = FindChild<T>(child); if (childElement != null) break;
                }
                else
                {
                    childElement = (T)child; break;
                }
            } return childElement;
        }
    }
}
